School Science and Mathematics Volume 20 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 edition. Excerpt: ... acquired considerable twist. Now, let go of tho pail and allow the cord to untwist. What position does the water take in tho pail? What position does the sawdust take? What would be the relative positions of tho cream and milk wero they subjected to the same experiment as the water and sawdust? This preliminary laboratory work has put the student in a position to attack his project with intelligence. They are now ready to suggest how cream is separated from the milk in a cream separator. If this experiment is carried on in the city where the children cannot see a separator in actual use on a farm, it would be possible to have them examine one at some farm implement dealer's. It would be much better to loan one and have it at the school. Then all pupils who are interested might glean some knowledge of such an apparatus. Some of the pupils should be asked to demonstrate and describe the cream separator to the class. The Babcock butter tester will almost always come up with the cream separator. One student might be asked to make a test with this apparatus before the class. At this time it would be quite fitting for the teacher to do some demonstrations on centrifugal apparatus, and to enlarge upon the meaning of centrifugal force. The project may end here, for you have accomplished all and more than you started out to find, but in the purposed book you will find after this project, references in literature about the centrifuges in which crystals of sugar and salt are dried in the process of refining, and also references to explain the fact that planets revolve about the sun in nearly circular orbits because of the combined influence of gravity and inertia. The project should be enlarged upon by the students reading as many of these...